Your stuff looks pretty good! 
It seems, to me, that you might be fighting your learning curve. You’ve learned a lot of stuff, really quickly and have done well. Now, when it’s time to move up to the next level, you find that you’re having a harder time and get discouraged.
Don’t worry! It’s normal. Everybody has “learning curve issues.”
The first thing I suggest is taking a break. Back off for a while. Let your mind settle and let what you’ve learned sink in. If you are, indeed, having learning curve issues, pushing harder will only discourage you more and you could even find yourself slipping backward. Give yourself some time to process what you’ve learned, already.
Spend some time away from Blender. Maybe watch a few tutorials or, better, buy a book and read it but, mostly, just put Blender down.
Your work is good! I like the trolley car and the bicycle! What do YOU think you need to work on?
I don’t see very many materials. Maybe you could switch modes and step away from modelling and teach yourself shading and making materials. Use models that you’ve already made as starting points. Another thing you could work on is lighting and scene design.
It’s really up to you, though. If you prefer to make models and you don’t like shading and materials, don’t worry about it. Go with modeling. In the real world, many people specialize. There are people who specialize in modeling, shading, lighting, animation and all sorts of things. Just look at the credits of any Pixar movie. You’ll see names of dozens of people, each with their own specialty. That’s the way movies are made! Go with your specialty if you want!
Still, my first advice is to step away from Blender and go outside, for a while. Hey! It’s SUMMER! Get out and enjoy the warm weather before winter comes!
Too many people think that being an artist means sitting in front of your canvas, paint brush in hand, bearing down on every detail of your work. (Or the computer analogy of pounding your keyboard.
) No! True creativity and true art are usually made when the artists is AWAY FROM his art! Getting up and out of the studio or the computer office allows the artist time to relax and absorb new ideas. If you chain yourself to your computer, you’ll only stagnate. Remember Jack Torrence (Jack Nicholson) in “The Shining?”… All work and no play makes Jack a dull boy! All work and no play makes Jack a dull boy. All work and no play makes Jack a dull boy…
So, get up, get your ass outside and enjoy some of this nice weather we’ve been having before it gets cold again! Will ya’?!
